Debt is when something, usually money, is owed by one party, the borrower or debtor, to a second party, the lender or creditor. Debt is a deferred payment, or series of payments, that is owed in the future, which is what differentiates it from an immediate purchase. The debt may be owed by sovereign state or country, local government, company, or an individual. Commercial debt is generally subject to contractual terms regarding the amount and timing of repayments of principal and interest. Loans, bonds, notes, and mortgages are all types of debt. The term can also be used metaphorically to cover moral obligations and other interactions not based on economic value. For example, in Western cultures, a person who has been helped by a second person is sometimes said to owe a "debt of gratitude" to the second person.